Mechanical stoker



Feb. 28, 1928. 1,660,542

P. N. BROWN MECHANICAL STOKER Filed July 3, 1924 2 Sheets-Sheet 1 IIIS OTTORNA'X Feb. 28, 1928.

P. W. BROWN MECHANICAL STOKER Filed July 5, 1924 2 Sheets-Sheet 2 Patented Feb. 28, 1928.

PERCY WILLIAM BROWN, OF DERBY, ENGLAND.

MECHANICAL STOKER.

Application filed July 3, 1924, Serial 1\To. 723,961, and. in Great Britain September 21, 1923.

In a mechanical stoker in which the grate iurface consists of a multiplicity of small members, these are apt to swell as an effect of the alternate heating and cooling to which 5 they are subjected and in consequence the air spaces of the grate are apt to become in a large measure closed. Further, the air spaces between adjacent members may become filled with particles of ash which under the influence of heat tend to solidify and adhere to the members, thus reducing and perhaps closing the air spaces. By the present invention the construction is such that the small members may grow considerably without impairing the air spaces and, by a further feature of the invention, such that in the normal operation of the grate the members when inverted assume an altered position relatively to each other so that any ash which has found a lodgment may become dislodged.

The members are so made that each can turn on its point of support or on one of its points of support and normally rest against its neighbour, provision being made for the necessary air space between them; should a member swell it turns on its points of support or one of its points of support and the air remains substantially constant.

For example, the point of support or one of the points of support for each member is offset from the vertical line through the centre of gravity, so that when the members are in the normal position each rests against an adjacent member or against the frame which retains them, the air spaces being formed for instance by small projections or pads upon the upper part of each member. Should a member swell, under the influence of heat, it

49 will merely change its inclination slightly,

still making contact with the adjacent member where the pads occur and preserving the air space practically unaltered. Provision is made in the frame which retains the said members to permit of this changein their inclination.

In forms of travelling grate in which the members become inverted in the course of I their travel, the invention provides that as it 50 comes into the inverted position each member turns on its support so as to increase the distance beween itself and the next member whereby any ash which has lodged in the air space may fall away. Thus in the case of members which can turn on their support as described above, the construction may be such that when in the inverted position the point of support of each member is arranged so that the inclination of the inset piece is reversed and that part of the member, which normally forms the grate surface, moves with relation to the adjacent member in creasing what was the air space, allowing fine dust or ashes to fall away shortly after it has been deposited and before it has had time to become baked and adherent to the grate surface.

The construction is illustrated by the accompanying drawings in which Fig. 1 is a transverse section of a grate bar of a chain travelling stoker, on line l-l of Fig. 2, and Fig. 2 is a longitudinal section on line 22 of Fig. 1. Fig. 8 is a plan of one of the grate members, and Fig. 4 is a part transverse section of the stoker showing the relative position of the parts when the upper run of the chain becomes the lower run.

The stoker is made up in known manner of a number of grate bars (1 having cheeks I) and a flange 0 which is bolted to the bar Z of the stoker chain. The cheeks I) carry the pin d on which the grate members 6 are threaded. It will be seen that the perforation 7 which allows the threading of the grate member is conical; also that each member has a rounded boss 9 near each end which is adapted to rest against the inclined face it of the next member. The airspace thus secured is also maintained by ribs i on the other side of the member. For the rest, the shape of the member is determined by the necessity that it should rest at one end on an inclined face of a grate bar and at the other end on a like face of the next bar, and by the consideration that the mem ber should be as light as possible compatibly with the requisite strength.

Owing to the bosses g and the ribs 2' the members may swell or grow considerably without choking the air spaces, and since the point is at which the member is supported is offset from the vertical line through the centre of gravity of the member, the constant position of the latter resting against its neighbour, or against a check I), is ensured.

As seen in Fig. 4, when the upper run becomes the lower run the members have tipped laterally on their points of support until an element of the conical surface of the perforation of each of them substantially coincides with an element of the surface of outwardly pivotal vmovement of the fuel supporting member about the pin ('ZI Also as tllBzPlVQ't pin d is of smaller diameter than the apertures in said members through which the pin-extends, both. ends of said members are permitted to drop a limited distance by gravity as the members reach the lower run of the grate. Thus the fuel supporting members are capable of both pivotal and outwardly bodily movements, which insures the dislodgment' of any ashes or otherparticles that may be in the air spaces between them,.as they reach the lower run of the grate.

Having thus fully described the nature of thesaid invention and the best means I know of carrying the same into practical efiect, I'claim:

l. A traveling grate stoker having, in

combination, fuel supporting members arranged s1de by s1de 1n a row, each of saidmembers having'a lateral projection adjacent its. fuel supporting surface, the center of gravity of each of said members being offset so as to tend to cause the member when in fuel supporting position to tip laterally to positlon said projection against the adjacent side of the adjacent member, and when in inverted position to tip laterally in the oppositedirection toscparatesaid projection from said adjacent member, and means for supporting said members so as to permit said. tipping movements thereof. 7

2. .Agtraveling grate stoker having, in combination, fuel supporting members arrangedside by side in a row, and means for supporting said members, said fuel supporting membersand said supporting means being constructed and. arranged to cause said members to lean laterally one upon the other when in fuel supporting position, and to. be separated from each other when in inverted position. j 3. A traveling grate stoker having, in

combination,v fuel supporting members "an ranged s1de by side 1n a row, ad acent, members having one a lateral projection adjacent its fuel. supporting surface and the other an inclined surface upon which said projection is adapted to rest, the center of gravity of. said members being oflsetso as to tend. to cause the members-when in fuel supporting position to tip laterally to positionsaid projections down upon said in olined portions, and means for supporting said members so as to permit said tipping movement thereof;

4. A traveling grate stoker .having, in

combination, fuel supporting members arranged side by side in a row, adjacent members having one a lateral projection adjacentv its fuel. si'ipporting surface and the other an inclined surface upon which said projection is adapted to rest, the center of gravity of said members being offset so as to tend to cause the members when in fuel supporting position to tip laterally to position said iro ections down upon said inclined surfaces, said members having frusto-conical apertures extending transversely there-' through having their larger ends opening out through the sides of said members bearing said projections, and a rod upon which said members are mounted I extending through said apertures and of smaller diameter than the smallest diameters thereof.

5. A traveling grate stokcr having, in

combination, fuel supporting members'arranged side by side in a row, adjacent members, having one a lateral projection adjacent its fuel supporting surface and the other an inclined surface upon which said projec tion is adapted to rest, the center of gravity of said members being offset so as to tend to cause the members when in fuel supporting position to tip laterally to position said.

projections down upon said inclined surfaces, said members having frusto-conical apertures extending transversely there through adjacent their forward ends, and means for supporting the rear ends of said members constructed to permit said lateral tipping movement of said members and limited outward movement thereof.

' 6. A traveling grate stoker having, in combination, fuel supporting members arranged side by side in a row, the adjacent sides of adjacent members having one a laterally inclined longitudinally extending portion adjacent'its fuel I supporting surface and the other a lateral. projection extending longi tudinally thereof and overlying said inclined portion, and means for supporting said members so as to permit lateral tipping movement thereof, the centers of gravity. of

llu

said members being located so as to tend to cause the members to tip in a directionto cause said lateral projections to rest upon said inclined portions. 7. A traveling grate stoker'ha'ving, in combination, fuel supporting members ar ranged side by side ina rowQadjacent members having one a lateral projection adjacent its fuel supporting surface, and the other an inclined portion upon which said projection isadapted to rest, the center of gravity of said members" being offset so as to tend to cause the members-when in fuel supporting position to tip laterally to position said projections down upon said inclined portions, and when in inverted position to tip in the opposite direction to separate said projections and said inclined portions, and means for supporting said members so as to permit such tipping movement thereof.

8. A traveling grate stoker having, in combination, fuel supporting members arranged side by side in a row, said members having their centers of gravity offset so as to tend to cause them to lean laterally one upon the other, and when in inverted position to be separated from each other, and means for supporting said members so as to permit such lateral tipping movement thereof.

9. A traveling grate stoker having, in combination, fuel supporting members arranged in rows extending transversely of the stoker with the members of each row arranged side by side and with the members of the several rows arranged end to end, each of said members having a frustoconi- I cal aperture adjacent its forward end and spaced a distance below its fuel supporting surface with the apertures in the members of each row similarly arranged, a rod extending through said apertures of the members of each row and of smaller diameter than the smaller diameters of said apertures so as to permit lateral tipping movement of said members on said rod, a 'bar extendin be tween adjacent ends of said members OI adjacent rows and having inclined surfaces upon which the ends of said members rest, the rear ends of said members and said bar having cooperating portions for limiting the outward movement of said rear ends but permitting limited outward movement thereof, the adjacent sides of the members of each row having one a lateral projection adjacent its fuel supporting surface and the other an inclined surface portion upon which said projection rests when said members are in fuel supporting position, the projections of each members being on the side thereof adjacent the larger end of its frusto-conical aperture.

In testimony whereof I have signed my name to this specification.

PERCY WILLIAM BROWN.

GERTIFHQATE @F iIQRPiECTIQN.

Patent No. 1, eat, 542. Granted February 28, 1.928, to

PERQY WILLIAM BROWN It is hereby certified that errer appears in the printed specification of ge 1, l ine 29,

the above numbered patent requiring correction as fol lows: Pa after the word air" insert the werd "space"; and that the said Letters Patent should be read wi tit this correct ion therein that the same may conform to the record of the ease in the Patent Qfiiee,

Signed and sealed this Zfith day of March, A. D. 1928.

M. 3. Moore,

Acting Commissioner of Patents.

Seai.

CERTIHCATE or eoeeeetlen.

Patent N0. 1, 660, 542. Granted February 28, 1928, to

PERQY WILLEAM BROWN It is hereby certified that error appears in the printed specification of 1, line 29,

the above numbered patent requiring correction as fol lows: Page after the Word "air" insert the word "space"; and that the said Letters Patent should be read wi th this correction therein that the same may conform to the record of the case in the Patent 0ttice,

Signed and seated this 20th day of March, A. D. 1928.

Rt. E. Moore,

Acting Commissioner of Patents.

Seal. 

